With the rapid development of information technologies, people require more and more bidirectional interactive services such as Internet access, Video on Demand (VOD), videoconference, videophone, telemedicine, and tele-education. Operators have an urgent need of carrying out such network Value Added Services (VASs) to increase the network operation revenue.
A bidirectional interactive service requires two paths: a forward path for carrying outbound traffic, and a backward path for carrying inbound traffic, to implement the interaction. The traffic in the two directions may be carried over one bidirectional Label Switched Path (LSP) or two specified unidirectional LSPs in two opposite directions, or by other means. A key to ensuring Quality of Service (QoS) of a bidirectional interactive service and deploying the bidirectional interactive service massively is to detect, locate and handle faults in a simple and efficient way.
For a bidirectional interactive service, a fault in one direction may affect or even lead to termination of the service in the other direction, and therefore, the troubleshooting needs to be performed in both directions simultaneously. In other circumstances that involve detection of faults in two directions, it is also necessary to detect, locate and handle the faults in the forward path and the backward path simultaneously, and a technology for detecting and handling the faults in two directions is also required. Besides, a bidirectional troubleshooting tool, which is capable of detecting the forward path and the backward path simultaneously, is required due to the emergence of bidirectional LSPs to detect two directions of a bidirectional LSP simultaneously. A bidirectional LSP may include a forward LSP and a backward LSP that have the same route and the same LSP Identifier (ID), or may include a forward unidirectional LSP and a backward unidirectional LSP that have different LSP IDs and may have different nodes and different links except that the first nodes of the two LSPs are the same.
However, the troubleshooting tools in the prior art such as LSP Ping and LSP Trace generally support only the unidirectional handling mode. If the fault detection is required on the forward path and the backward path respectively, it is necessary to operate the troubleshooting tool on both sides respectively, and detect, locate and handle the faults on both sides independently, and it is necessary to transmit connectivity fault information and switching information between both sides in time to implement protection switching in both directions simultaneously. This handling mode increases the signaling and processing overhead, network load, complexity of operation and maintenance, and the operation cost, and can hardly meet the troubleshooting requirements of bidirectional interactive services.